Two people are dead and 19 others  -- including an infant -- were injured after at least one person opened fire in Scarborough late Monday night, prompting Toronto Police Chief Bill Blair to call this incident the worst case of gun violence the city has ever seen.

Those dead have only been identified by police as a young teenaged girl and a 20-year-old man. Police will not release their identities until their families are notified of their death.

The shooting happened at around 10:30 p.m. when a fight broke out during an outdoor party at 193 Danzig St. in the Morningside Avenue and Lawrence Avenue East area.

Hundreds of people were present for a community barbecue at the time and it is believed more than one person fired a gun.

One infant suffered a gunshot wound but the child is in stable condition, according to Toronto police spokeswoman Const. Wendy Drummond.

Another person staggered to a nearby laundromat with a gunshot wound to the back, according to witnesses at the scene.

"We have had a tragic, terrible incident," an audibly distressed Blair told reporters at a news conference from the scene.

"It is difficult to describe -- this is unprecedented," he said. "In my 35 years of policing, this is the worst incident of gun violence anywhere in North America and the worst crime in Toronto's history."

Drummond told CP24 that she could not confirm the ages of those hurt in the shooting but said not all 19 victims were shot. Some of those transported to hospital were being treated for shock.

Sixteen ambulances were used to transport people to area hospitals.

Blair said one of the injured is a person of interest in the case and is in police custody.

He also said this area of Scarborough does not typically see this level of violence. Six shootings have been reported in the area since the start of the year.

Toronto Mayor Rob Ford said he is "disgusted" by the violence in a statement he issued to the media.

"I am shocked and disgusted by this senseless act of violence," he said. "While we try to understand this tragic event, I want to assure residents that this horrific, criminal behaviour will not be tolerated in our city."

Police are appealing to anyone with information to come forward and speak with investigators.

@SandieBenitah is on Twitter. For instant breaking news, follow @CP24 on Twitter.